1. Field of the Invention
The present invention relates generally to wireless networks and, more particularly, to systems and methods for automatically placing or moving nodes in a wireless network to provide biconnectivity.
2. Description of Related Art
Advances in electronics and mechanics have provided the basic technologies required for sophisticated robots. It is well recognized that robots have significant operational advantages over humans because they can perform tasks without requirements for rest, food, shelter, or task heterogeneity. This makes them potentially useful in future military exercises on the battlefields (so much so that they may end up undertaking all of the missions their human counterparts perform today), in several disaster relief situations (search and rescue), in cleaning cavities and surfaces that are otherwise cumbersome to clean, in collection of soil and samples on the surface of Mars (distributed sensing), in undertaking routine tasks in flexible manufacturing environments and supermarkets, and in many other scenarios. Most of the aforementioned tasks need collaboration among different robot units for their timely and efficient completion.
Robotics researchers have proposed the use of centralized robotic networks, where all members of a team of robots communicate with a central controller (e.g., base station) over a wireless medium. In most application scenarios, such as the ones described in the previous paragraph, it is difficult to guarantee the presence of a wireless base station that can coordinate the flow of information between any two robot units. Moreover, the movement of robots can be severely restricted in order to keep in communication range of the base station. This can hamper the task that the robot team plans to execute.
There has arisen a need for self-forming, self-healing, and self-organizing multihop communications networks capable of use with autonomous and semi-autonomous robotic systems. Although numerous ad hoc network protocols, such as packet radio, mobile ad hoc networks (MANETs), or self-organizing networks, have been proposed and implemented, all of them were designed to be completely transparent to applications. One of the main reasons for adopting this approach is that the protocols are intended to be used with a wide variety of platforms and applications. The resulting extended applicability, however, comes at the cost of severe restrictions in the exchange of information between the application and the network, making it virtually impossible for them to anticipate each other's behavior and, thus, cooperate.
In robotic systems, cooperation among the robotic applications is highly desirable because robotic applications generally entail movement, which directly affects the communication network. Conversely, the propagation of radio transmissions used for communication may be able to provide an additional way of sensing the environment. Such interaction is a feasible proposition because robots are unique in their integrated design in that the mission control, motion control, and networking protocols are typically all implemented within the same architecture.
Ad hoc networks that include robotic nodes have a salient difference from standard MANETs. In the former networks, for example, the position and motion of nodes is controllable from other nodes in the network. In the latter networks, motion is determined by the owner of the node and is not usually controllable.
As a result, there continues to be a need for self-forming, self-healing, and self-organizing multihop communications networks capable of use with autonomous and semi-autonomous robotic systems.